ORCHARD PARK, N.Y. (AP) — Bills starting safety Jordan Poyer was ruled out from playing against the Miami Dolphins this weekend, potentially opening the door for Damar Hamlin to appear in his first regular season game since going into cardiac arrest during a game in January.

Poyer hasn’t practiced this week due to a knee injury. It’s unclear when he was hurt, and coach Sean McDermott hasn’t revealed the extent of the injury except for listing the seven-year starter as day to day on Thursday.

Poyer’s absence on Sunday will likely lead to primary backup Taylor Rapp filling the starting spot alongside Micah Hyde. The injury could also lead to Hamlin making his season debut after being a healthy inactive through the first three games.

Appearing in a regular-season game would mark the final step in Hamlin’s bid to resume his playing career and what’s been described as the 25-year-old’s remarkable recovery after going into cardiac arrest and needing to be resuscitated on the field during a game at Cincinnati on Jan. 2.

Since being cleared to resume playing in April, the backup safety has showed no signs of tentativeness in passing every on-field test he’s faced in making the Bills 53-player roster last month. The third-year player combined for nine tackles in appearing in all three of Buffalo’s preseason games in August.

Hamlin was hurt while making what appeared to be a routine tackle, when his heart stopped from a direct blow at a specific point in the heartbeat that can cause cardiac arrest. Doctors have assured Hamlin he could resume playing without setbacks or complications.

Hamlin was starting in place of Hyde, who was sidelined by a season-ending neck injury sustained in Week 2.

The outing on Sunday is regarded as an early season showdown between AFC East rivals Miami (3-0) and Buffalo (2-1).

Buffalo’s secondary will be tested by a Dolphins offense coming off a 70-20 win over Denver last week. It features the receiving tandem of Tyreek Hill and Jaylen Waddle, who has been cleared to play after missing one game in the NFL’s concussion protocol.

BY JOHN WAWROW